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61 Cards in this Set
- Front
- Back
what happens in glycolysis? (in general)
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glucose and a six carbon sugar is changed into two molecules of pyruvate (a three carbon molecule).
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where does glycolysis occur?
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cytoplasm
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what are the main stages of glycolysis?
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phosphorylation, lysis, oxidation, ATP formation
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What is phosphorylation?
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adding a phosphate group
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What is used to phosphorylate the hexose?
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2 ATP molecules
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What is the result of phosphorylation?
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a hexose biphosphate and 2 ADP molecules
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What is the purpose of phosphorylation?
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The energy of the hexose is raised and this makes the subsequent reactions possible.
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What is lysis?
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Splittling of the hexose biphosphate into two molecules of triose phosphate.
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What is oxidation?
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Oxidation occurs when an element loses 1/more elections in a reaction with other elements
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What happens during the oxidation in glycolysis?
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2 hydrogen atoms are removed from each triose phosphate molecule and attaches to NAD+ and forms NADH
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What happens after oxidation?
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The energy released by this oxidation links on another phosphate group, producing a 3-carbon compound + 2 phosphate groups.
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How is pyruvate formed?
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By removing the 2 phosphate groups and by passing them to ADP which results in ATP formation
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What energy causes ATP formation from ADP?
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An endergonic reaction (a reaction that absorbs energy from environment)
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What are the products of glycolysis?
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1 glucose converted into 2 pyruvates (six carbon into 2 three carbon molecules), NET GAIN of 2 ATP molecules, 2 NAD+ converted into 2 NADH+ H+
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If there is no oxygen what happens to the pyruvate?
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Fermentation occurs.
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What is fermentation?
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The anaerobic breakdown of glucose that results in a gain of 2 ATP molecules and end products such as alcohol and lactate.
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Why does the process of fermentation occur after glycolysis?
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To gain back the NAD+ used up in glycolysis and because there is no oxygen, won't be able to accept electrons in the ETC.
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Where does the link reaction occur?
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Mitochondria
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How does the pyruvate enter the mitochondria?
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From the outer membrane through diffusion
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Why is it able to enter through the outer membrane?
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It is "leaky" and so it's permeable to small ions and molecules
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How does pyruvate enter the matrix?
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By the carrier proteins in the inner mitochondrial membrane
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What happens during the link reaction? (in general)
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Pyruvate-->Acetyl CoA
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How does the pyruvate convert to an acetyl CoA?
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Through oxidative decarboxylation
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Describe the process of oxidative decarboxylation
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The enzyme pyruvate dehydrogenase removes one hydrogen and one CO2 molecule from pyruvate and attach it to CoA, resulting in the acetyl CoA.
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What happens o the acetyl group in the first reaction of the Kreb's cycle?
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It is transferred to a 4-carbon compound (oxalaoacetate) to form a 6-carbon compound (citrate).
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Name the first reaction in kreb's cycle and what does it do?
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Decarboxylation; CO2 removed and excreted as waste.
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What does oxidation in kreb's cycle do?
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Removes the hydrogen in 4 of the reactions. in 3 of the oxidations, hydrogen accepted by NAD+ and the other by FAD
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What happens to the energy released by these oxidation reactions?
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Mostly stored by the carriers when they accept hydrogen. This energy is later released by the ETC to make ATP.
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How is ATP produced from the kreb's cycle?
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Directly from the substrate-level phosphorylation.
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What are the products of the Kreb's cycle for 1 pyruvate molecule?
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1 ATP, 2 CO2, 3 NADH, 1 FADH
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What are the products of the Kreb's cycle for 1 glucose molecule?
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2 ATP, 4 CO2, 6 NADH, 2 FADH2
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What is the main purpose of the kreb's cycle?
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To transfer high energy electrons from carbon molecules to electron carriers (NADH, FADH2)
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Where do these electron carriers (NADH, FADH2) go after the Kreb's cycle?
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Electron Transport Chain
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What is the electron transport chain?
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A series of electron carriers located in the inner membrane of the mitochondria.
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What supplies two electrons to the first carrier in the chain?
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NADH
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Where did these electrons come from?
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From oxidation reactions in earlier stages of cell respiration.
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How do the electrons pass along the ETC?
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by giving up energy each time the pass from one carrier to the next.
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How is ATP made from this process?
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By using the energy to phosphorylate ADP molecules to form ATP at 3 points along the chain.
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Why is chemiosis also called oxidative phosphorylation?
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The energy available from a molecule of glucose is released during a series of OXIDATION reactions, and is transferred to a molecule of ATP in the form of a PHOSPHATE bond.
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What is ATP synthase?
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Transports the protons back across the membrane down the concentration gradient.
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What pumps protons across the inner mitochondrial membrane?
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energy released as electrons pass the ETC
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What drives ATP production during H+ movement across the membrane?
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The rotation of parts of ATP synthase as H+ moves across the membrane.
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What is concentration gradient?
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A store of potential energy
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Why is the concentration gradient important?
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To control the energy available from the oxidation reactions in glycolysis and the Krebs Cycle.
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What's oxygen's role at the end of the ETC?
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Since NAD+ is in limited supply in the matrix, the electrons that were being passed down are accepted by oxygen, and a water molecule is formed.
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Why is oxygen so important?
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Without oxygen, there is no ultimate electron acceptor, and the NADH can never be converted back to NAD+.
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What will happen if there is no NAD+?
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Without NAD+ the Krebs cycle cannot proceed, and the cell must proceed through fermentation.
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How many ATP molecules formed after chemiosis?
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32 or 34
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What happens to the NADH and FADH molecules?
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Gives up their electrons and return NAD+ and FAD+
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How many molecules of water were produced?
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6
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How does the outer mitochondrial membrane contribute to cellular respiration?
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It separates the contents of the mitochondria from the rest of the cell, creating a compartment with ideal conditions for aerobic respiration?
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How does the matrix contribute to cellular respiration?
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The matrix is the fluid inside the mitochondria contains enzymes for the Krebs cycle and the link reaction.
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How does the space between inner and outer membranes contribute to cellular respiration?
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this space is very small, thus a high proton concentration can easily be formed in chemiosis when protons are being pumped into this space by the ETC.
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How does the cristae contribute to cellular respiration?
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the tubular shapes of the inner membrane increases the surface area available for oxidative phosphorylation.
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How does the inner mitochondrial membrane contribute to cellular respiration?
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the inner membrane contains ETC and ATP synthase which carry out chemiosis
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What's reduction?
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when an element GAINS 1/more electrons when reacting with other elements.
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What are redox reactions?
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any reaction in which the reactants have their oxidation state changed.
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What's an oxidation state?
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the charge on an element if all of its bonded elements (and their shared electrons) are removed.
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Anabolic pathways?
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uses energy to convert simple-->complex molecules
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Catabolic pathways?
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uses energy to break bonds so complex-->simple molecules
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What are "pathways"?
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a series of chemical reactions that occur in order, the product of one being used as the reactant for another.
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